Technological advances have provided various sectors of society like government, industry, commerce and entertainment with access to networked information in order to increase operational and commercial efficiencies. Mobile data communications is evolving quickly because of global communication networks and devices such as the Internet, intranets, laptops, PDAs (personal digital assistants) and increased requirements of workforce mobility. Moreover, third generation mobile system (3G) technologies (e.g., UMTS-Universal Mobile Telecommunications System) are being developed and are considered enhancements to GSM (Global System for Mobile telecommunications) cellular standards.
3GPP (Third generation partnership project) standards define an IMS (IP Multimedia Subsystem) architecture that provides a horizontal layered architecture with a common IP (Internet Protocol)-based connectivity for services. The IMS architecture enables convergence of data, speech and mobile network technology over an IP-based infrastructure and enhances real time, multimedia mobile services such as rich voice services, video telephony, messaging services, conferencing, and push services. Specifically, the IMS standard defines a generic architecture for offering Voice over IP (VoIP) and multimedia services for both wireless and wireline access. VoIP services provide increased mobility, for example, subscribers can log on with their chosen device at different locations and their calls can be routed to them. However, the increased mobility increases the complexity involved with determination of accurate location information, employed during emergency calls.
A fixed line telephone has a direct relationship between its telephone number and a physical location and thus the physical location for emergency calls originating from that number is known. Accordingly, the emergency call can be routed to PSAP (Public Safety Answering Point) that is closest to the physical location, such that, emergency crew can respond in the shortest possible time. With VoIP services, users can be mobile and determination of a current physical address when an emergency call is received can be tedious, complex and/or inaccurate. Some conventional systems collect location information and/or contact information from subscribers. The onus is on the subscriber to provide the location information, but the VoIP provider must provide the customer with a means of updating this information. However, for nomadic wireline users, the overhead of constantly having to update location information can be time consuming and tedious. Another shortcoming of VoIP E911 is that the emergency system is based on a static table lookup. Unlike in cellular phones, where the location of an E911 call can be traced using GPS, cellular triangulation, or other methods, the VoIP E911 information is only accurate so long as subscribers are diligent in keeping their emergency address information up-to-date.